Tunable antenna systems

ABSTRACT

An electronic device has wireless communications circuitry including an adjustable antenna system coupled to a radio-frequency transceiver. The adjustable antenna system may include one or more adjustable electrical components that are controlled by storage and processing circuitry in the electronic device. The adjustable electrical components may include switches and components that can be adjusted between numerous different states. The adjustable electrical components may be coupled between antenna system components such as transmission line elements, matching network elements, antenna elements and antenna feeds. By adjusting the adjustable electrical components, the storage and processing circuitry can tune the adjustable antenna system to ensure that the adjustable antenna system covers communications bands of interest.

This application is a continuation of patent application Ser. No.14/737,394, filed Jun. 11, 2015, which is a continuation of patentapplication Ser. No. 12/831,180, filed Jul. 6, 2010, now U.S. Pat. No.9,070,969, which is hereby incorporated by reference herein in itsentirety. This application claims the benefit of and claims priority topatent application Ser. No. 14/737,394, filed Jun. 11, 2015 and patentapplication Ser. No. 12/831,180, filed Jul. 6, 2010, now U.S. Pat. No.9,070,969.

BACKGROUND

This relates generally to wireless communications circuitry, and moreparticularly, to electronic devices that have tunable antenna systems.

Electronic devices such as computers and handheld electronic devices areoften provided with wireless communications capabilities. For example,electronic devices may use long-range wireless communications circuitrysuch as cellular telephone circuitry to communicate using cellulartelephone bands. Electronic devices may use short-range wirelesscommunications links to handle communications with nearby equipment. Forexample, electronic devices may communicate using the WiFi® (IEEE802.11) bands at 2.4 GHz and 5 GHz and the Bluetooth® band at 2.4 GHz.

To satisfy consumer demand for small form factor wireless devices,manufacturers are continually striving to implement wirelesscommunications circuitry such as antenna components using compactstructures. However, it can be difficult to fit conventional antennastructures into small devices. For example, antennas that are confinedto small volumes often exhibit narrower operating bandwidths thanantennas that are implemented in larger volumes. If the bandwidth of anantenna becomes too small, the antenna will not be able to cover allcommunications bands of interest.

In view of these considerations, it would be desirable to provideimproved wireless circuitry for electronic devices.

SUMMARY

An electronic device may be provided with wireless communicationscircuitry including an adjustable antenna system coupled to aradio-frequency transceiver. The adjustable antenna system may includeone or more adjustable electrical components that are controlled bystorage and processing circuitry in the electronic device. By adjustingthe adjustable electrical components, the storage and processingcircuitry can tune the adjustable antenna system to ensure that theadjustable antenna system satisfactorily covers communications bands ofinterest.

The adjustable electrical components may include switches that can beplaced in open or closed positions. The adjustable electrical componentsmay also include components that can be continuously or semicontinuouslyadjusted to produce various resistances, capacitances, and inductances.Antenna system adjustments may be made to transmission line structures,matching networks, antenna resonating elements, antenna grounds, andantenna feeds.

An antenna may have portions that are formed from conductive electronicdevice housings. An electronic device may have a rectangular periphery.A conductive peripheral member such as a display bezel or housingsidewall member may surround the periphery of the housing. One or moredielectric gaps may be interposed in the conductive peripheral member.The adjustable electrical components may be used to bridge the gaps.Control signals may be applied to the adjustable electrical componentsto adjust the size of the gap and other antenna system parameters andthereby tune the antenna system.

Further features of the invention, its nature and various advantageswill be more apparent from the accompanying drawings and the followingdetailed description of the preferred embodiments.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of an illustrative electronic device withwireless communications circuitry in accordance with an embodiment ofthe present invention.

FIG. 2 is a schematic diagram of an illustrative electronic device withwireless communications circuitry in accordance with an embodiment ofthe present invention.

FIG. 3 is circuit diagram of illustrative wireless communicationscircuitry having fixed and adjustable antenna structures in anelectronic device in accordance with an embodiment of the presentinvention.

FIG. 4 is a graph showing how antenna structures can be adjusted duringoperation to cover communications bands of interest in accordance withan embodiment of the present invention.

FIG. 5 is a graph showing how antenna structures can be adjusted duringoperation to fine tune antenna response during operation in accordancewith an embodiment of the present invention.

FIG. 6 is a diagram of wireless communications circuitry in anelectronic device showing how a transceiver circuit may feed an antennausing a transmission line and a matching network in accordance with anembodiment of the present invention.

FIG. 7 is a diagram of an illustrative antenna that may be used inwireless communications circuitry in an electronic device in accordancewith an embodiment of the present invention.

FIG. 8 is a diagram of showing how wireless circuit components such asantenna system structures may be coupled using an adjustable electricalcomponent in accordance with an embodiment of the present invention.

FIG. 9 is a diagram of showing how wireless circuit components such asantenna system structures may be coupled using an adjustable electricalcomponent such as a switch in accordance with an embodiment of thepresent invention.

FIG. 10 is a diagram of showing how wireless circuit components such asantenna system structures may be coupled using an adjustable electricalcomponent such as a circuit element with continuously orsemicontinuously tunable electrical properties in accordance with anembodiment of the present invention.

FIG. 11 is a diagram of showing how wireless circuit components such asantenna system structures may be coupled using an adjustable electricalcomponent such as a tunable capacitor with a continuously orsemicontinuously tunable capacitance in accordance with an embodiment ofthe present invention.

FIG. 12 is a diagram of showing how wireless circuit components such asantenna system structures may be coupled using an adjustable electricalcomponent such as semicontinuously a tunable electrical network withswitches that provide the network with multiple selectable impedancevalues in accordance with an embodiment of the present invention.

FIG. 13 is a circuit diagram of an adjustable antenna system in anelectronic device in accordance with an embodiment of the presentinvention.

FIG. 14 is a diagram of an adjustable antenna system in an electronicdevice showing how the antenna system may be adjusted by adjustingtransmission line loading in accordance with an embodiment of thepresent invention.

FIG. 15 is an interior perspective view of an illustrative electronicdevice having a peripheral conductive member and an internal planarconductive member showing how an adjustable electrical component maybridge gaps in the peripheral conductive member in accordance with anembodiment of the present invention.

FIG. 16 is a perspective view of an interior portion of a peripheralconductive electronic device housing member showing how adjustableelectrical components may be bridge gaps in the peripheral conductivemember in accordance with an embodiment of the present invention.

FIG. 17 is a top view of an electronic device showing how an adjustableelectrical component may be used to connect different parts of aninternal planar conductive member in accordance with an embodiment ofthe present invention.

FIG. 18 is a diagram of an illustrative antenna in which an adjustableelectrical component has been used to couple different parts of anantenna ground plane element in accordance with an embodiment of thepresent invention.

FIG. 19 is a diagram of an illustrative electronic device having aconductive peripheral housing member and an internal planar structurewith multiple regions that have been coupled using an adjustableelectrical component in accordance with an embodiment of the presentinvention.

FIG. 20 is a perspective view of an illustrative radio-frequencytransceiver circuit that has been mounted to a rigid printed circuitboard and that has been coupled to a flex circuit on which conductiveantenna structures are coupled to conductive flex traces and an optionalflex-mounted component by an adjustable electrical component inaccordance with an embodiment of the present invention.

FIG. 21 is a diagram of an adjustable antenna system in which acomponent with conductive structures such as a flex circuit on which acamera or other device structure has been mounted may be coupled toportions of an antenna using adjustable electrical components inaccordance with an embodiment of the present invention.

FIG. 22 is an exploded perspective view of an illustrative electronicdevice having components such as a radio-frequency transceiver circuitthat uses an adjustable antenna system that includes conductive framemembers and an adjustable electrical component in accordance with anembodiment of the present invention.

FIG. 23 is a top view of an illustrative electronic device showing howan adjustable antenna system may be formed using an adjustableelectrical component that couples a conductive peripheral housing memberto a conductive planar internal housing member in accordance with anembodiment of the present invention.

FIG. 24 is a flow chart of illustrative steps involved in operating anelectronic device with an adjustable antenna system in accordance withan embodiment of the present invention.

DETAILED DESCRIPTION

Electronic devices such as device 10 of FIG. 1 may be provided withwireless communications circuitry. The wireless communications circuitrymay be used to support wireless communications such as long-rangewireless communications (e.g., communications in cellular telephonebands) and short-range communications (i.e., local area network linkssuch as WiFi® links, Bluetooth® links, etc.). The wirelesscommunications circuitry may include one or more antennas. The antennasand associated wireless communications circuits within the electronicdevices may be adjustable. Adjustable antenna systems may be tuned toadjust antenna response within a band (i.e., the antenna systems may befine tuned). Fine tuning may be used to ensure that signals in a desiredcommunications band are received properly. Adjustable antenna systemsmay also be tuned so that an antenna response curve that would otherwiseonly cover a single band or group of bands can be used to coveradditional frequencies of interests (i.e., the antenna systems may becoarsely tuned to cover a different band or group of bands). Coarsetuning may allow relatively narrow bandwidth antennas to be tuned tocover communications bands over a relatively wide range of frequencies.

Any suitable electronic devices (e.g., device 10 of FIG. 1) may beprovided with adjustable antenna systems that have these types of fineand coarse tuning capabilities. For example, adjustable antenna systemsmay be used in electronic devices such as desktop computers, gameconsoles, routers, laptop computers, computers embedded in a computermonitor or television, computers that are part of set-top boxes or otherconsumer electronics equipment, relatively compact electronic devicessuch as portable electronic devices, etc. The use of portable electronicdevices is sometimes described herein as an example. This is, however,merely illustrative. Adjustable antenna systems may be used in anyelectronic device.

Electronic devices such as illustrative electronic device 10 of FIG. 1may be laptop computers, tablet computers, cellular telephones, mediaplayers, other handheld and portable electronic devices, smaller devicessuch as wrist-watch devices, pendant devices, headphone and earpiecedevices, other wearable and miniature devices, or other electronicequipment.

As shown in FIG. 1, device 10 includes housing 12. Housing 12, which issometimes referred to as a case, may be formed of materials such asplastic, glass, ceramics, carbon-fiber composites and other composites,metal, other materials, or a combination of these materials. Device 10may be formed using a unibody construction in which most or all ofhousing 12 is formed from a single structural element (e.g., a piece ofmachined metal or a piece of molded plastic) or may be formed frommultiple housing structures (e.g., outer housing structures that havebeen mounted to internal frame elements or other internal housingstructures).

Device 10 may, if desired, have a display such as display 14. Display 14may, for example, be a touch screen that incorporates capacitive touchelectrodes. Display 14 may include image pixels formed fromlight-emitting diodes (LEDs), organic LEDs (OLEDs), plasma cells,electronic ink elements, liquid crystal display (LCD) components, orother suitable image pixel structures. A cover glass member may coverthe surface of display 14. Buttons such as button 16 may pass throughopenings in the cover glass. Openings may also be formed in the coverglass of display 14 to form a speaker port such as speaker port 18.Openings in housing 12 may be used to form input-output ports,microphone ports, speaker ports, button openings, etc.

Wireless communications circuitry in device 10 may be used to formremote and local wireless links. One or more antennas may be used duringwireless communications. Single band and multiband antennas may be used.For example, a single band antenna may be used to handle Bluetooth®communications at 2.4 GHz (as an example). As another example, amultiband antenna may be used to handle cellular telephonecommunications in multiple cellular telephone bands. Other types ofcommunications links may also be supported using single-band andmultiband antennas.

If desired, device 10 may use multiple antennas. Multiple antennas may,for example, be used to support an antenna diversity scheme. With anantenna diversity scheme, control circuitry in device 10 may monitorsignal quality or sensor data to determine which antenna or antennas areperforming best or are otherwise desirable to use (e.g., to satisfyregulatory limits). Based on these considerations, the control circuitrymay then choose to use only a subset of the antennas or may otherwiseadjust antenna use. If, for example, a sensor or a signal qualitymeasurement determines that one of two antennas in an antenna diversityarrangement has become blocked by an external object such as part of ahuman body, the control circuitry may temporarily inactivate thatantenna.

Device 10 may also use multiple antennas to implement amultiple-input-multiple-output (MIMO) communications protocol. In a MIMOscheme, each of the antennas in a system may handle an independent datastream, allowing overall data throughput to be increased. The controlcircuitry in device 10 may use proximity data or other data to controloperation of the multiple antennas in the MIMO setup. For example, thecontrol circuitry may temporarily switch from MIMO operation to aprotocol that uses only a single antenna or may switch from afour-antenna MIMO scheme to a two-antenna MIMO scheme, etc.

Antennas may be located at any suitable locations in device 10. Forexample, one antenna may be located in an upper region such as region 22and another antenna may be located in a lower region such as region 20.In a larger device, antennas may be located along device edges, in thecenter of a rear planar housing portion, in device corners, etc.

Antennas in device 10 may be used to support any communications bands ofinterest. For example, device 10 may include antenna structures forsupporting local area network communications (e.g., IEEE 802.11communications at 2.4 GHz and 5 GHz for wireless local area networks),signals at 2.4 GHz such as Bluetooth® signals, voice and data cellulartelephone communications (e.g., cellular signals in bands at frequenciessuch as 850 MHz, 900 MHz, 1800 MHz, 1900 MHz, 2100 MHz, etc.), globalpositioning system (GPS) communications at 1575 MHz, signals at 60 GHz(e.g., for short-range links), etc.

Different antennas may handle different bands or a communications bandor group of bands may be handled using a shared antenna. One antenna indevice 10 may, for example, be used in handling voice and datacommunications in one or more cellular telephone bands, whereas anotherantenna in device 10 may provide coverage in a first band for handlingGlobal Positioning System (GPS) signals at 1575 MHz and a second bandfor handling Bluetooth® and IEEE 802.11 (wireless local area network)signals at 2.4 GHz (as examples). Additional antennas may be provided toimplement antenna diversity schemes, phased antenna arrays (e.g., at 60GHz), additional bands, etc.

A schematic diagram showing illustrative components that may be used indevice 10 of FIG. 1 is shown in FIG. 2. As shown in FIG. 2, device 10may include storage and processing circuitry 28. Storage and processingcircuitry 28 may include storage such as hard disk drive storage,nonvolatile memory (e.g., flash memory or otherelectrically-programmable-read-only memory configured to form a solidstate drive), volatile memory (e.g., static or dynamicrandom-access-memory), etc. Processing circuitry in storage andprocessing circuitry 28 may be used to control the operation of device10. This processing circuitry may be based on one or moremicroprocessors, microcontrollers, digital signal processors,application specific integrated circuits, etc.

Storage and processing circuitry 28 may be used to run software ondevice 10, such as internet browsing applications,voice-over-internet-protocol (VOIP) telephone call applications, emailapplications, media playback applications, operating system functions,etc. To support interactions with external equipment, storage andprocessing circuitry 28 may be used in implementing communicationsprotocols. Communications protocols that may be implemented usingstorage and processing circuitry 28 include internet protocols, wirelesslocal area network protocols (e.g., IEEE 802.11 protocols—sometimesreferred to as WiFi®), protocols for other short-range wirelesscommunications links such as the Bluetooth® protocol, cellular telephoneprotocols, MIMO protocols, antenna diversity protocols, etc. Antennasystem tuning operations may be controlled using software stored andrunning on device 10 (i.e., stored and running on storage and processingcircuitry 28 and/or input-output circuitry 30).

Input-output circuitry 30 may include input-output devices 32.Input-output devices 32 may be used to allow data to be supplied todevice 10 and to allow data to be provided from device 10 to externaldevices. Input-output devices 32 may include user interface devices,data port devices, and other input-output components. For example,input-output devices may include touch screens, displays without touchsensor capabilities, buttons, joysticks, click wheels, scrolling wheels,touch pads, key pads, keyboards, microphones, cameras, buttons,speakers, status indicators, light sources, audio jacks and other audioport components, digital data port devices, light sensors, motionsensors (accelerometers), capacitance sensors, proximity sensors, etc.

Input-output circuitry 30 may include wireless communications circuitry34 for communicating wirelessly with external equipment. Wirelesscommunications circuitry 34 may include radio-frequency (RF) transceivercircuitry formed from one or more integrated circuits, power amplifiercircuitry, low-noise input amplifiers, passive RF components, one ormore antennas, transmission lines, and other circuitry for handling RFwireless signals. Wireless signals can also be sent using light (e.g.,using infrared communications).

Wireless communications circuitry 34 may include radio-frequencytransceiver circuitry 90 for handling various radio-frequencycommunications bands. For example, circuitry 34 may include transceivercircuitry 36, 38, and 42. Transceiver circuitry 36 may handle 2.4 GHzand 5 GHz bands for WiFi® (IEEE 802.11) communications and may handlethe 2.4 GHz Bluetooth® communications band. Circuitry 34 may usecellular telephone transceiver circuitry 38 for handling wirelesscommunications in cellular telephone bands at 850 MHz, 900 MHz, 1800MHz, 1900 MHz, and 2100 MHz data band (as examples). Circuitry 38 mayhandle voice data and non-voice data. Wireless communications circuitry34 can include circuitry for other short-range and long-range wirelesslinks if desired. For example, wireless communications circuitry 34 mayinclude 60 GHz transceiver circuitry, circuitry for receiving televisionand radio signals, paging system transceivers, etc.

Wireless communications circuitry 34 may include global positioningsystem (GPS) receiver equipment such as GPS receiver circuitry 42 forreceiving GPS signals at 1575 MHz or for handling other satellitepositioning data. In WiFi® and Bluetooth® links and other short-rangewireless links, wireless signals are typically used to convey data overtens or hundreds of feet. In cellular telephone links and otherlong-range links, wireless signals are typically used to convey dataover thousands of feet or miles.

Wireless communications circuitry 34 may include antennas 40. Antennas40 may be formed using any suitable antenna types. For example, antennas40 may include antennas with resonating elements that are formed fromloop antenna structure, patch antenna structures, inverted-F antennastructures, slot antenna structures, planar inverted-F antennastructures, helical antenna structures, hybrids of these designs, etc.Different types of antennas may be used for different bands andcombinations of bands. For example, one type of antenna may be used informing a local wireless link antenna and another type of antenna may beused in forming a remote wireless link antenna.

With one suitable arrangement, device 10 may have antennas in regions ofdevice 10 such as upper region 22 and lower region 20. One or more upperantennas for device 10 may be formed in region 22. One or more lowerantennas for device 10 may be formed in region 20. In devices with otherform factors such as laptop and tablet computers, wearable devices,computer monitors with integrated computers, etc., antennas may belocated in other suitable regions (e.g., at the four corners of arectangular device, on front and back surfaces, along edge regions of adevice, in one or more arrays, etc.).

As shown in FIG. 3, transceiver circuitry 90 may be coupled to antennas40 using transmission lines 140. Device 10 may have antennas 40 thatinclude both fixed antenna structures (e.g., fixed antenna structures40A) and adjustable antenna structures (e.g., adjustable antennastructures 40B). A configuration that includes both fixed and adjustableantennas may be used, for example, when there is sufficient spaceavailable for only one broadband antenna. In this type of arrangement,fixed antenna structures 40A may use a broadband design that coversmultiple communications bands, whereas adjustable structures 40B may usea narrowband design that achieves multiband coverage through use ofcoarse antenna system tuning. Other configurations may also be used. Forexample, device 10 may be provided exclusively with adjustable antennastructures. In general, any suitable number of adjustable antennas maybe provided in device 10 (e.g., one adjustable antenna, two adjustableantennas, three adjustable antennas, four or more adjustable antennas,etc.).

When device 10 includes an adjustable antenna system (i.e., whenantennas 40 and associated wireless circuitry 34 in device 10 isadjustable), antenna performance can be altered in real time. Forexample, the resonance curve of the antenna system may be slightlyaltered to compensate for environmental factors such as temperaturechanges. Relatively small adjustments to the frequency response of anantenna system are sometimes referred to as fine tuning adjustments orfine tuning. If desired, the frequency response of the antenna systemcan be adjusted by larger amounts. For example, the frequency responseof an antenna may be altered sufficiently to cause the antenna to coverdifferent communications bands.

A standing wave ratio (SWR) versus frequency plot for an illustrativeantenna system in device 10 is shown in FIG. 4. In the FIG. 4 example,the antenna system operates in two modes. In a first mode of operation,the antenna system is characterized by a frequency response of the typeillustrated by solid line 142. As shown in FIG. 4, this frequencyresponse allows the antenna system to cover two communications bands(i.e., a first communications band centered at frequency f_(a) and asecond communications band centered at frequency f_(b)). In a secondmode of operation, the antenna system is characterized by a frequencyresponse of the type illustrated by dashed line 144. When operating inthe second mode of operation, the antenna system may cover onecommunications band at frequency f_(c) and another communications bandat frequency f_(d). Frequency bands f_(a) and f_(b) may be, for example,850 MHz and 900 MHz frequency bands, whereas frequency bands f_(c) andf_(d) may be, for example, 1900 MHz and 2100 MHz frequency bands (asexamples). During operation of device 10, device 10 can determine whichcommunications bands are to be used and can adjust the adjustableantenna system accordingly (i.e., to cover the frequency rangeassociated with curve 142 or to cover the frequency range associatedwith curve 144).

If desired, device 10 may include a fixed antenna such as the fixedantenna of FIG. 3 that covers both low bands (f_(a) and f_(b)) and highbands (f_(c) and f_(d)). As described in connection with FIG. 4, device10 may also have an adjustable antenna system that is adjusted betweenthe first and second modes to selectively cover the same bands that arecovered by the fixed antenna.

An illustrative fine tuning operation using an adjustable antenna systemin device 10 is shown in FIG. 5. As shown in FIG. 5, the adjustableantenna system may initially exhibit a frequency response of the typeshown by solid line 146. Due to changes in operating temperature orother effects, the frequency response of the antenna may need to beadjusted to ensure that signals are properly received and transmitted.This can be accomplished by adjusting the adjustable antenna system indevice 10 so that its frequency response shifts slightly to thefrequency response shown by dashed line 148 (i.e., a frequency shift ofΔf). Real time adjustments such as the fine tuning adjustments of FIG. 5and the coarse tuning adjustments of FIG. 4 may be made to ensure thatdevice 10 performs as desired under a variety of wireless traffic andenvironmental scenarios.

FIG. 6 shows illustrative components that may be included in anadjustable antenna system in electronic device 10. As shown in FIG. 6,radio-frequency signals may be generated and received by radio-frequencytransceiver circuitry 90. Circuitry 90 may include radio-frequencytransmitters for transmitting radio-frequency signals andradio-frequency receivers for receiving radio-frequency signals.Radio-frequency amplifier circuitry and other components (e.g.,switches) may be included in transceiver circuit block 90.

Adjustable antenna system 150 may include antennas 40, matching network152, and transmission line 140.

Antenna 40 may be include antenna ground structures and antennaresonating element structures such as loop antenna structures, patchantenna structures, inverted-F antenna structures, slot antennastructures, planar inverted-F antenna structures, helical antennastructures, hybrids of these designs, etc.

Transmission line 140 may be coupled to transceiver circuitry 90.Transmission line 140 may be based on a microstrip transmission linestructure, a stripline transmission line structure, an edge coupledmicrostrip transmission line structure, an edge coupled striplinetransmission line structure, transmission line structures formed onflexible printed circuits (“flex circuits”), structures formed on rigidprinted circuit boards, a coaxial cable, other suitable transmissionline structures, or combinations of these structures.

Matching network 152 may be used to help match the impedance oftransmission line 140 to the impedance of antenna 40. Matching network152 may include electrical components such as resistors, inductors, andcapacitors, and conductive traces, pieces of metal, and other structuresthat have associated resistances, inductances, and capacitances.Although shown as being interposed between transmission line 140 andantenna 40 in the example of FIG. 6, matching network components may, ifdesired, be interposed within transmission line 90 and/or within antenna40. The arrangement of FIG. 6 is merely illustrative.

Antenna 40 may be fed using an antenna feed such as an antenna feedformed from positive antenna feed terminal 156 and ground antenna feedterminal 158.

To provide antenna system 150 with adjustability, antenna system 150 maybe provided with one or more adjustable electrical components. Thesecomponents may be incorporated into antenna 40 (including the antennafeed), matching network 152, and transmission line 140.

FIG. 7 is a diagram of an illustrative antenna. In the FIG. 7 example,antenna 40 has an inverted-F configuration. This is, however, merelyillustrative. Antenna 40 may be formed using any suitable antennadesign.

As shown in FIG. 7, antenna 40 may include an antenna ground (e.g.,antenna ground element 160) and an antenna resonating element (antennaresonating element 162).

Antenna ground 160 and antenna resonating element 162 may be formed fromconductive structures such as pieces of metal, metal traces on printedcircuit boards, parts of an electronic device housing, conductivecomponents, and other conductive elements in device 10. Antenna groundelement 160 may be formed from one conductive structure or multipleconductive structures. Antenna resonating element 162 may have a mainresonating element branch such as branch 164 and additional branches.Segment 166 of resonating element 162 may short arm 164 to ground 160.

Transceiver 90 may be coupled to antenna feed terminals 156 and 158.Matching network components and transmission line structures are notshown in FIG. 7 to avoid over-complicating the drawing.

Antenna 40 and the other structures of antenna system 150 may beprovided with adjustable electrical components such as switches andcontinuously and semicontinuously tunable electrical components. Forexample, an adjustable electrical component may be coupled betweenportions of antenna resonating element arm 164 or between portions ofground plane 160 in an antenna of the type shown in FIG. 4. Adjustableelectrical components may also be incorporated into matching network 152or transmission line 140 of FIG. 6. The antenna feed for antenna 40 maybe adjusted using adjustable electrical components (e.g., adjustableelectrical components coupled to feed terminals).

The use of an adjustable electrical component to make adjustments toadjustable antenna system 150 is illustrated in FIG. 8. As shown in FIG.8, adjustable antenna system 150 may include adjustable antenna systemportions 150A and 150B. Portions 150A and 150B may be antenna resonatingelement structures, antenna ground element structures, parasitic antennastructures (e.g., antenna structures that are near-field coupled toother antenna structures) antenna feed structures, other antennastructures, matching network structures, transmission line structures(e.g., a transmission line stub), other antenna system structures, orany combination of these structures.

Adjustable electrical component 168 may have a first terminal such asterminal 170 that is connected to antenna system portion 150A and asecond terminal such as terminal 172 that is connected to antenna systemportion 150B. Adjustable electrical component 168 may be adjusted usingcontrol signals applied to control input 174 or may be implemented usinga two-terminal arrangement in which control signals are applied overterminals 170 and 172. Examples of adjustable electrical components thatmay be used for adjustable electrical component 168 include switches,variable resistors, variable capacitors, variable inductors, andcomponents that control multiple electrical parameters.

FIG. 9 shows how adjustable electrical component 168 may be implementedusing a switch. Switch 168 of FIG. 9 may be placed in an open state inwhich antenna system portion 150A is electrically isolated from antennasystem portion 150B or may be placed in a closed state in whichterminals 170 and 172 are shorted together so that portions 150A and150B are electrically connected. Switch 168 may be implemented using agallium arsenide field-effect transistor (FET), a microelectromechanicalsystems (MEMs) switch, a metal-oxide-semiconductor field-effecttransistor (MOSFET), a p-i-n diode, a high-electron mobility transistor(HEMT), a pseudomorphic HEMT (PHEMT), a transistor formed on asilicon-on-insulator (SOI) substrate, etc.

As shown in FIG. 10, adjustable electrical component 168 may beimplemented using a component that can be placed in numerous differentstates (e.g., a component that is continuously variable or that issemicontinuously variable and can be placed in one of a number ofdifferent discrete states). Component 168 may be, for example, acontinuously variable capacitor, a semicontinuously adjustable capacitorthat has 2-100 or more different capacitance values, a continuouslyvariable resistor, a semicontinuously adjustable resistor that has 2-100or more different resistance values, a continuously variable inductor,or a semicontinuously adjustable inductor that has 2-100 or moredifferent inductance values. FIG. 11 shows, for example, how adjustableelectrical component 168 may include a continuously variable capacitor.Semicontinuously adjustable components may be implemented using arraysof discrete components and switches configured to serve as multiplexers.

If desired, adjustable electrical component 168 may be formed from otheradjustable electrical components. As shown in FIG. 12, for example,semicontinuously adjustable electrical component 168 may be formed froman electrical network that includes inductors such as inductors L1 andL2. Switches (e.g., switches SWA and SWB in the FIG. 12 example) may beused to form desired patterns of electrical connections within theelectrical network. For example, components may be switched into or outof use or may be interconnected in different ways. In the FIG. 12example, the inductance that is exhibited between terminals 170 and 172may be adjusted by opening and closing switches SWA and SWB in variouspatterns. Networks with other patterns of electrical components (e.g.,capacitors, resistors, inductors, and conductive and dielectricstructures that have capacitance, inductance, and resistance and thatserve as capacitors, resistors, and inductors), other patterns ofswitches or continuously or semicontinuously adjustable components mayalso be used in implementing adjustable electrical component 168. Theexample of FIG. 12 is merely illustrative.

An illustrative adjustable antenna system 150 that is based on aninverted-F antenna such as antenna 40 of FIG. 7 is shown in FIG. 13.Main resonating element arm 164 of antenna 40 may be connected to ground160 through a short circuit path such as path 132A (if switch 176 isclosed and switch 178 is open) or path 132B (if switch 176 is open andswitch 178 is closed). A feed path (see, e.g., terminals 158 and 108),and one or more optional paths such as the path formed by adjustableelectrical component 120 (e.g., a switch), the path formed by element122 (e.g., a semicontinuously or continuously adjustable component), andthe path formed by adjustable electrical components 124 and 126 (e.g., aswitch and a continuously adjustable component, respectively). Optionalantenna resonating element branches such as branch 130 may be coupled toantenna 40 (e.g., by connecting branch 130 to main resonating elementarm 164 through adjustable electrical component 128).

Antenna 40 may be feed by transceiver 90 (i.e., transceiver circuitrysuch as transceiver circuitry 90 of FIG. 2). Transmission line 140 mayhave paths such as positive antenna signal paths 94 and 104 and groundantenna signal paths such as paths 92 and 106 and may be used to conveyradio-frequency antenna signals between transceiver 90 and antenna 40.

Matching circuitry 152 may be interposed in the path between transceiver90 and antenna 40. Matching circuitry 152 may include series-connectedand shunt-connected adjustable electrical components such as components102 and 100. One or more adjustable electrical components such ascomponents 100 and 102 may be coupled between transmission line 140 andadditional transmission line components and other electrical components.For example, a component such as a transmission line stub (e.g.,transmission line stub 140′), may be coupled to transmission line 140via component 100. Any of the adjustable electrical components used inadjustable antenna system 150 may include transmission line structures,if desired.

Transmission line paths such as positive transmission line path 104 andground transmission line path 106 may be used to interconnect matchingcircuitry 152 to the antenna feed of antenna 40. The antenna feed mayhave a fixed or tunable configuration. In the example of FIG. 13, theantenna feed for antenna 40 is tunable between a first antenna feedconfiguration in which switch 118 (or other such adjustable electricalcomponent) has a first position and a second antenna feed configurationin which switch 118 has a second position. When switch 118 is in itsfirst position, terminal 108 is connected to terminal 156A, so thatterminal 156A serves as the positive antenna feed terminal for antenna40. When switch 118 is in its second position, terminal 108 is connectedto terminal 156B, so that terminal 156B serves as the positive antennafeed terminal for antenna 40.

Feed terminals 156A and 156B are located at different positions alongthe length of main resonating element arm 164, so the impedance andtherefore the frequency response of antenna 40 can be adjusted by usingswitch 118 to control the feed location in antenna 40. The arrangementof FIG. 13 is merely illustrative. In general, antennas such as antenna40 in device 10 may have tunable feeds formed from two or more feedpoints, tunable feeds that involve one, two, three, or more than threeswitches, feeds that are tuned by adjusting the ground antenna feedand/or the positive antenna feed, non-tunable feeds, etc.

By incorporating adjustable electronic components into antenna 40 (e.g.,antenna resonating element 162), antenna 40 may be adjusted ad describedin connection with FIGS. 4 and 5. For example, the size and shape ofantenna structures such as resonating element 162 in antenna 40 can becontrolled by storage and processing circuitry 28. In the FIG. 13arrangement, adjustable electrical component 128 may be, for example, aswitch with two states (e.g., an open state that electricallydisconnects antenna resonating element portion 130 from antennaresonating element portion 164 and a closed state that electricallyconnects antenna resonating element portion 130 and antenna resonatingelement portion 164). Component 128 may adjust the size and shape of theantenna resonating element and thereby adjust the frequency response ofthe antenna as described in connection with FIGS. 4 and 5. Additionalresonating element structures and antenna structures may likewise beselectively connected and disconnected from the antenna resonatingelement in antenna 40 if desired. Circuit components (e.g., resistors,inductors, and capacitors) may be interconnected with switches such asswitch 128 (e.g., for impedance matching). Antenna 40 may also beadjusted by controlling components such as adjustable components 120,122, 124, and 126 (as examples).

The adjustable components of FIG. 13 are sometimes depicted asadjustable electronic component 168 in the other drawings. FIG. 14 showshow adjustable antenna system 150 may include an adjustable transmissionline. Adjustable transmission line 140 may include one or moreadjustable electronic components such as adjustable electronic component168. Adjustable electronic component 168 may be used to selectivelyadjust the properties of transmission line 140. For example, component168 may be used to connect transmission line stub 140′ to a maintransmission line path in transmission line 140 and may be used todisconnect transmission line stub 140′ from the main transmission linepath in transmission line 140. By adjusting the properties oftransmission line 140, the frequency response of the antenna (i.e.,adjustable antenna system 150) can be controlled as described inconnection with FIGS. 4 and 5 (as examples).

FIG. 15 is an interior perspective view of electronic device 10 of FIG.1 showing how electronic device 10 may include conductive structuressuch as conductive peripheral member 180. Device 10 may have arectangular outline (periphery) when viewed from the front (i.e., whenviewed from the face of device 10 that contains display 14). Conductiveperipheral member 180 may be implemented using metal or other conductivematerials. Conductive peripheral member 180 may surround substantiallyall of the rectangular periphery of device 10. Conductive peripheralmember 180 may have the shape of a display bezel for display 14 or atrim structure for device 10 (i.e., a bezel or trim piece that runsaround the upper rim on the front of device 10) or may be implementedusing a flat or curved member that forms housing sidewalls that coversubstantially all of the sides of housing 12 (as examples). A gap ormultiple gaps such as gaps 182 may be interposed in conductiveperipheral member 180. Gaps 182 may be formed from dielectric (e.g.,air, plastic, glass, ceramics, composites, other dielectrics, orcombinations of these materials). Gaps 182 may form part of the antennasin device 10 (e.g., antenna 40).

Transceiver 90 may be implemented using components such as one or moreintegrated circuits and other electrical components that are mounted ona substrate such as printed circuit board 194. Transmission line tracesin board 194 (i.e., transmission line 140A may be coupled betweentransceiver 90 and radio-frequency connector 186. Connector 186 may beconnected to a coaxial cable segment or other transmission line 104B.Transmission line 104B may be coupled to a matching network (e.g.,matching network 152 of FIG. 13) and an antenna feed (e.g., an antennafeed made up of antenna feed terminals 158 and 156). The antenna feedmay, for example, be coupled across one of gaps 182 or may be locatedelsewhere in device 10.

Adjustable electrical components 168 may be included in antenna 40 tohelp provide adjustable antenna system 150 with adjustability. As anexample, an adjustable electrical component may bridge one of gaps 182(e.g., by connecting one of components 168 between terminals 190 and 192on opposing sides of a gap in peripheral conductive member 180).Adjustable electrical components 168 may also be connected between theother conductive components in adjustable antenna system 150 (e.g.,between a first terminal such as terminal 198 that is attached toperipheral conductive member 180 and a second terminal such as terminal188 that is connected to a conductive trace in board 194 (e.g., a groundplane trace).

Devices such as device 10 of FIG. 15 may, if desired, have planarmembers such as illustrative planar structure 196. Structure 196 mayform part of the rear housing surface (i.e., an external housing wallstructure on the rear face of housing 12) or may form an internal planarmember (e.g., an internal housing structure that spans the width ofdevice 10 while creating closed or open slot-shaped openings such asdielectric-filled opening 184 at one or both ends of device 10 as shownin FIG. 15). Structure 196 may be formed from metal (e.g., a metalplate) or other conductive structures and may, if desired, be used informing an antenna ground plane for antenna 40.

Adjustable electrical components 168 may be used to provideadjustability to the size of gaps 182 in conductive peripheral member180. Consider, as an example, the illustrative arrangement shown in FIG.16. As shown in FIG. 16, a peripheral conductive member in device 10such as peripheral conductive member 180 may have multiple adjacent gaps182. In the FIG. 16 example, peripheral conductive housing member 180has two gaps 182 a first of which has a length (width) of G1 and asecond of which has a length (width) of G2. Adjustable electricalcomponents 168A and 168B may bridge gaps 182 (e.g., on the interior sideof peripheral conductive member 180). For example, adjustable electricalcomponent 168A may have a first terminal that is electrically connectedto portion 200 of peripheral conductive member 180 and a second terminalthat is electrically connected to portion 202 of peripheral conductivemember 180. Adjustable electrical component 168B may have a firstterminal that is electrically connected to portion 202 of peripheralconductive member 180 and a second terminal that is electricallyconnected to portion 204 of peripheral conductive member 180. As withthe other adjustable electrical components 168 for device 10, adjustableelectrical components 168 of FIG. 16 may be implemented using switches,continuously or semicontinuously variable components such as variablecapacitors, variable resistors, and variable inductors, continuously orsemicontinuously adjustable circuit networks, etc.

Configurations of the type shown in FIG. 16 may be used to adjust theelectrical properties of gaps 182 and/or to adjust effective gap length(i.e., to electrically adjust gap width). As shown in FIG. 16, forexample, there may be a gap length (width) G3 between the outermost(most distant) edges of gaps 182. Adjustable components 168 may be, forexample, switches. In this type of configuration, switch 168A may beopened to switch the leftmost gap 182 into use or may be closed tobypass the leftmost gap. Switch 168B may be opened to switch therightmost gap 182 into use or may be closed to bypass the rightmost gap.When both switches 168A and 168B are open, antenna 40 has two gaps (ofwidths G1 and G2) connected in series within peripheral conductivemember 180, so the gaps may be considered to have an effective width ofG3. When switch 168A is closed and switch 168B is open, only the gap ofwidth G2 is present. When switch 168B is closed and switch 168A is open,only the gap of width G1 is present. When both switches 168 are closed,no gap is present. Adjustment of the states of switches 168A and 168B(e.g., by applying control signals from storage and processing circuitry28 to switches 168) can therefore adjust the width of the gap inconductive peripheral member 180. When adjustable electrical componentsother than switches are used (e.g., variable capacitors, inductors,etc.) a combination of impedance adjustments and effective gap widthadjustments may be produced.

In the example of FIG. 16, adjustable electrical components 168 connectdifferent portions of peripheral conductive member 180 to each other.Adjustable electrical components 168 may also be used to connect otherconductive portions of antenna system 150 together such as otherconductive portions of housing 12. As an example, adjustable components168 and may be used to couple together different portions of a planarstructure such as structure 196 of FIG. 17. Structure 196 may be formedusing all or some of a rear housing structure (e.g., a housing wall), aninternal housing member, or other conductive structures.

Member 196 may, for example, have an opening such as opening 184′ ofFIG. 17. Opening 184′ may be contiguous with opening 184 and may form anextension of opening 184. Opening 184 (and extension 184′) may form anopening for antenna 40 (e.g., an opening for a slot antenna, a loopantenna, a hybrid antenna, etc.).

Opening 184 may have an inner periphery P. The length of inner peripheryP and other electrical properties of antenna 40 may be adjusted byadjusting electrical components 168. For example, by using switches forcomponents 168, the size of opening 184′ and therefore the length of Pmay be adjusted. If switch 168C and 168D are both open, the size ofextension 184′ and length P will be maximized. If switch 168C is openand switch 168D is closed, the size of opening 184′ will be halved (asan example). Switch 168C (and, if desired switch 168D) may be closed toreduce the size of opening 184′ further (or even to bypass opening 184′entirely). Antenna 40 may exhibit a resonance peak when P is equal toabout one wavelength of the radio-frequency antenna signals beinghandled by antenna 40. By adjusting P, the frequency response of antenna40 can therefore be adjusted as described in connection with FIGS. 4 and5 (i.e., by adjusting the center frequency of a slot antenna or loopantenna, etc.).

FIG. 18 shows how antenna 40 in adjustable antenna system 150 may beadjusted by providing one or more adjustable electrical components 168between respective portions of ground plane 160. In the FIG. 18 example,ground plane 160 includes ground plane portion 160A and ground planeportion 160B. Adjustable electrical component 168 bridges gap 206between portions 160A and 160B. By controlling adjustable electricalcomponent 168, ground plane 160 can be altered (e.g., to include member160A while member 160B is disconnected from antenna 40) or to includeboth members 160A and 160B (i.e., by coupling members 160A and 160Btogether by bridging gap 206. Component 168 may, for example, be aswitch that can be opened to disconnect portion 160B from portion 160Aand that can be closed to connect portions 160A and 160B together.Component 168 may also be an adjustable component such as an adjustablecapacitor, adjustable resistor, adjustable inductor, or other adjustablecircuitry that can be adjusted to tune antenna 40.

If desired, ground plane 160 may be implemented using a planar structuresuch as planar structure 196 of FIG. 19. Structure 196 may be, forexample, an external housing structure (e.g., a planar rear housing wallin housing 12), an internal housing structure (e.g., an internal plateor other planer support structure), or other conductive structures.Structure 196 may have a dielectric gap such as gap 208 that separatesportions 160′ and 160″ of structure 196. Gap 208 may be bridged usingadjustable electronic component 168 (e.g., a switch, a continuouslyadjustable component, etc.), thereby tuning the performance of antenna40.

As shown in FIG. 20, transceiver 90 may be mounted on a substrate suchas a printed circuit board and coupled to an antenna 40 on a flexcircuit substrate (substrate 210) via transmission line 140.Transmission line 140 may, for example, include conductive traces inprinted circuit board 194 and conductive traces in flex circuit 210.Flex circuit 210 may be formed from a sheet of polyimide or otherflexible polymer sheet that serves as a printed circuit board.Conductive traces for antenna 40 (e.g., conductive metal antennaresonating element traces such as traces 212 and 214) may be formed onthe exposed outer surface of flex circuit substrate 210 or may be formedfrom internal conductive traces.

Adjustable electrical component 168 may bridge conductive antennastructures such as structures 212 and 214. Component 168 may be, forexample, a switch that can be opened to disconnect structure 214 fromstructure 212 or that can be closed to connect structures 214 and 212.Structures 212 and 214 may form part of a ground plane element, part ofantenna resonating element 162 (e.g., an arm such as arm 130 of FIG.13), part of a parasitic element (e.g., an antenna element whosepresence affects the frequency response of antenna system 150, but thatis near-field coupled to the antenna rather than being directly fed bytransmission line 140), etc. If desired, flex circuit 210 may be used asa substrate for one or more electrical components such as component 216.Components such as component 216 may be, for example, camera modules,speaker parts, button structures, integrated circuits, connectors, orother components (e.g., components that include conductive structuresthat may be connected to trace 214). These components may be mounted toflex circuit substrate 210 using parts of conductive traces 212 and 214or using separate conductive traces.

Consider, as an example, an arrangement in which electronic device 10includes a camera module. The camera module (e.g., one of input-outputdevices 32 of FIG. 2) may be mounted to flex circuit 210. Traces in flexcircuit 210 may be used to provide power and control signals to thecamera module and may be used to gather data signals from the cameramodule. Traces 214 and 212 may be formed on the same flex circuit as thecamera module, reducing component count and saving space in device 10.Adjustable electrical component 168 may be adjusted to selectivelyswitch into use conductive material on flex circuit 210 (e.g., tracessuch as traces 214 on flex circuit 210, conductive components associatedwith the camera module, conductive ground structures, etc.). In thisway, adjustments to adjustable electrical component 168 may be used totune antenna 40 and adjustable antenna system 150.

FIG. 21 is a diagram of adjustable antenna system 150 showing how acomponent such as component 218 may be coupled to antenna structuressuch as antenna resonating element 164 and antenna ground 160 using oneor more adjustable electrical components 168. Component 218 may be, forexample, a camera module (e.g., a camera module component on a flexcircuit as described in connection with component 216 on flex circuit210 of FIG. 20), a speaker, a button, a microphone, an input-outputconnector such as an audio jack or data connector, etc. One or both ofthe adjustable electrical components may be used in controllingadjustable antenna system 150. If desired, adjustable electricalcomponents 168 may be used to selectively couple component 218 to otheradjustable antenna system structures (e.g., transmission linestructures, matching circuit structures, feed structures, etc.).

FIG. 22 is a perspective view of an illustrative configuration that maybe used for electronic device 10. As shown in FIG. 22, electronic device10 may have a display such as display 14. Display 14 may include adisplay module 222 mounted beneath a transparent cover layer such ascover glass layer 220. Components such as transceiver 90 may be mountedwithin the interior of housing 12. Antenna 40 may include conductivestructures such as frame members 224 and 226. Antenna 40 may alsoinclude conductive structures such as antenna resonating elementstructures (e.g., conductive traces on a flex circuit, etc.), conductivestructures such as ground plane elements (e.g., a ground plane formedfrom conductive plate 196 of FIG. 15 and overlapping conductivestructures such as printed circuit boards, connectors, buttons,speakers, batteries, etc.), and other conductive structures.

In the FIG. 22 example, frame members 224 and 226 are mounted to housing12 using fasteners such as screws 228. If desired, other attachmentmechanisms may be used to attach frame members within housing 12 (e.g.,welds, adhesive, springs, engagement features such as protrusions andmating slots, etc.). Frame members 224 and 226 may be formed from metalor other conductive materials. Adjustable electrical component 168 maybe used to control how many frame members such as members 224 and 226are electrically connected within antenna 40 (e.g., to control the sizeof an antenna resonating element arm or ground plane) or may be used tocontrol other electrical antenna properties. This allows adjustableantenna system 150 to be tuned as described in connection with FIGS. 4and 5.

FIG. 23 shows how one or more adjustable electronic components such asadjustable electronic component 168 may be coupled between a groundplane element such as plate member 196 and a portion of peripheralconductive member 180 (e.g., a peripheral housing sidewall or bezelstructure). Adjustable component 168 of FIG. 23 may be, for example, aswitch that can be placed in an open or closed position. Portions ofperipheral conductive member 180 and opposing portions of conductivestructure 196 may define an opening such as opening 184 with an innerperiphery. Component 168 may bridge opening extension 184′. Opening 184(including extension 184′) may form a slot for a slot antenna or hybridantenna. The length of the inner periphery of opening 184 may beapproximately equal to one wavelength at an operating frequency ofinterest. Switch 168 may be closed to decrease the length of the innerperiphery (to length P) or can be opened to increase the length of theinner periphery (to length P′). Adjustments to component 168 maytherefore be used to control the frequency response of antenna 40.

The antenna system adjustment mechanisms described in connection withFIGS. 1-23 may, if desired, be used in any combination. For example,antenna system adjustments may be made using any combination oftransmission line adjustments, matching network adjustments, antennaadjustments, antenna feed adjustments, antenna resonating elementadjustments, antenna ground adjustments, etc. Adjustable electricalcomponents 168 may be incorporated into any combination of the portionsof antenna system 150 (e.g., to bridge ground gaps, to bridge portionsof an antenna resonating element, to connect a ground plate to aperipheral conductive member in a device housing, to connect portions ofa peripheral housing member together in various formations and therebyadjust the width of a dielectric gap in the peripheral housing member,to form connections between conductive antenna structures and housingframe members, to bridge any combination of these structures, etc.).

FIG. 24 is a flow chart of illustrative steps involved in operating anelectronic device with an adjustable antenna system such as electronicdevice 10 of FIG. 1.

At step 230, storage and processing circuitry 28 (FIG. 2) may be used todetermine which communications bands are to be used by device 10. Forexample, if signals are being transmitted over a 2.4 GHz local WiFilink, storage and processing circuitry 28 may conclude that adjustableantenna system 150 will be covering (or should continue to cover) the2.4 GHz communications band. Wireless communications in various cellulartelephone bands may also be supported. The operations of step 230 mayinvolve determination of the capabilities of device 10 (i.e., thecapabilities of transceiver 90), the current geographic location ofdevice 10 (e.g., the current country in which device 10 is located),current traffic being handled (e.g., determining what type of cellulartraffic or local area network traffic is currently being received on aparticular band), etc. Information on currently active bands or bandsthat need to be covered to receive incoming data may be gathered bymonitoring incoming traffic through a fixed antenna (e.g., in a systemof the types shown in FIG. 3 in which some antennas are fixed and someare adjustable) or by periodically cycling an adjustable antenna systemthrough all possible bands of interest. Information on bands that are tobe used for an upcoming activity (e.g., a data transmission activity)may be determined based on factors such as the last band used,geographic location, trial and error, look-up tables mapping deviceactivities to required band usage, etc.

At step 232, after having determined which communications bands are tobe covered by adjustable antenna system 150, storage and processingcircuitry 28 may, in response, issue corresponding control signals toadjustable antenna system 150. If, for example, storage and processingcircuitry 28 determines that adjustable antenna system 150 should coverthe 1900 MHz band, control signals may be issued to the adjustableelectrical components 168 in adjustable antenna system 150 to configureadjustable antenna system 150 to cover the 1900 MHz band (as anexample).

At step 234, the adjustable electrical component(s) 168 in adjustableantenna system 150 may be controlled by the control signals that havebeen issued, thereby tuning adjustable antenna system 150 coarsely(e.g., to cover a desired band as described in connection with FIG. 4)and/or finely (e.g., to improve tuning accuracy within a particularcommunications band as described in connection with FIG. 5).

The operations of FIG. 24 (e.g., monitoring to determine which bands areof interest, determining how to adjust components 168, and issuingcommands that adjust components 168 and therefore system 150) may beperformed repeatedly in real time (e.g., in response to the satisfactionof appropriate trigger criteria, periodically according to a schedule,continuously, etc.).

The foregoing is merely illustrative of the principles of this inventionand various modifications can be made by those skilled in the artwithout departing from the scope and spirit of the invention. Theforegoing embodiments may be implemented individually or in anycombination.

What is claimed is:
 1. An electronic device having a periphery,comprising: radio-frequency transceiver circuitry; an antenna having anantenna feed and ground plane structures; a transmission line pathcoupled between the radio-frequency transceiver circuitry and theantenna feed; peripheral conductive housing structures that run alongthe periphery and surround the ground plane structures, wherein theperipheral conductive housing structures include a portion that forms atleast part of the antenna; storage and processing circuitry configuredto generate a control signal; and an adjustable electrical componentcoupled to the peripheral conductive housing structures, wherein theadjustable electrical component has a control input that receives thecontrol signal and the adjustable electrical component is configured toadjust a frequency response of the antenna based on the control signal.2. The electronic device defined in claim 1, wherein the peripheralconductive housing structures include a dielectric-filled gap thatdivides the peripheral conductive housing structures.
 3. The electronicdevice defined in claim 2, wherein the peripheral conductive housingstructures include an additional dielectric-filled gap that divides theperipheral conductive housing structures.
 4. The electronic devicedefined in claim 3, wherein the dielectric-filled gap and the additionaldielectric-filled gap are formed at different sides of the electronicdevice.
 5. The electronic device defined in claim 2, wherein theadjustable electrical component comprises first and second terminalscoupled to the peripheral conductive housing structures at opposingsides of the dielectric-filled gap.
 6. The electronic device defined inclaim 1, wherein the adjustable electrical component comprises anadjustable electrical component selected from the group consisting of anadjustable capacitor and an adjustable inductor.
 7. The electronicdevice defined in claim 1, wherein the antenna comprises an inverted-Fantenna and the portion of the peripheral conductive housing structuresthat forms at least part of the antenna forms an antenna resonatingelement for the inverted-F antenna.
 8. The electronic device defined inclaim 1, wherein the electronic device has a length, a width that isless than the length, and a height that is less than the width, and theperipheral conductive housing structures extend across the height of theelectronic device.
 9. The electronic device defined in claim 8, whereinthe peripheral conductive housing structures extend across the lengthand the width of the electronic device.
 10. The electronic devicedefined in claim 1, wherein the antenna feed comprises a signal feedterminal coupled to the portion of the peripheral conductive housingstructures and a ground feed terminal coupled to the ground planestructures.
 11. An electronic device having a periphery and opposingfirst and second faces, the electronic device comprising: ground planestructures; peripheral conductive housing structures that run along theperiphery of the electronic device and surround the ground planestructures; a dielectric-filled gap in the peripheral conductive housingstructures that divides the peripheral conductive housing structuresinto first and second segments, wherein the second segment is separatedfrom the ground plane structures by a dielectric-filled opening, thedielectric-filled gap having a first end at the dielectric-filledopening and a second end at the first face of the electronic device; andan antenna formed from at least the second segment and the ground planestructures.
 12. The electronic device defined in claim 11, wherein thefirst segment is coupled to the ground plane structures.
 13. Theelectronic device defined in claim 12, wherein the ground planestructures comprise a conductive housing wall on the second face of theelectronic device.
 14. The electronic device defined in claim 13,further comprising a display on the first face of the electronic device.15. The electronic device defined in claim 11, further comprising: anadditional dielectric-filled gap in the peripheral conductive housingstructures that separates the second segment from a third segment of theperipheral conductive housing structures, the additionaldielectric-filled gap having a first end at the dielectric-filledopening and a second end at the first face of the electronic device. 16.The electronic device defined in claim 11, wherein the antenna comprisesan antenna feed having a first feed terminal coupled to the ground planestructures and a second feed terminal coupled to the second segment. 17.The electronic device defined in claim 11, further comprising: anadjustable electrical component coupled to the second segment; andstorage and processing circuitry configured to provide a control signalto a control input of the adjustable electrical component that tunes afrequency response of the antenna.
 18. An electronic device having aperiphery, a length, a width that is less than the length, and a heightthat is less than the width, comprising: ground plane structures;peripheral conductive housing structures that surround the ground planestructures, wherein the peripheral conductive housing structurescomprise a first sidewall extending across the width of the electronicdevice, a second sidewall extending from a first end of the firstsidewall along the length of the electronic device, and a third sidewallextending from a second end of the first sidewall along the length ofthe electronic device; a dielectric-filled opening having a firstportion extending from the second sidewall to the third sidewall andhaving a second portion that extends from an end of the first portionand that is interposed between the second sidewall and a portion of theground plane structures, wherein the portion of the ground planestructures is interposed between the second portion of thedielectric-filled opening and the third sidewall; and an antenna thatincludes a portion of the peripheral conductive housing structures. 19.The electronic device defined in claim 18, further comprising: anadjustable electronic component that bridges the second portion of thedielectric filled opening and that is configured to tune a frequencyresponse of the antenna.
 20. The electronic device defined in claim 18,wherein the peripheral conductive housing structures extend across theheight of the electronic device and include a fourth sidewall thatextends between the second and third sidewalls, and the ground planestructures include an additional portion that extends from the secondsidewall to the third sidewall.